Astronomer and historian. Around 1474 he wrote his "Great Treatise" HaHibur HaGadol under the patronage of the bishop of Salamanca which was translated into Spanish. His astronomical tables were used by Columbus. After the expulsion of 1492, he went to Portugal where he developed the copper Astrolabe used by Vasco Da Gama. In 1497 he was forced to flee or convert. He left and reached Tunis, where he wrote a history of the Jews from the creation until 1500.